Musical string instruments, such as the guitar, banjo, or mandolin and the like are provided with a string tuning device for each string mounted on the head of the instrument. This device, commonly referred to as a tuning key, is used to vary the tension of the string drawn over the fretted elongate neck portion of such instruments.
The common practice involves providing a winding spindle or drum for each string. The spindle is mounted on the head of the instrument and the string is wound several times around the winding spindle.
This procedure first provides a binding attachment of the string to the spindle or drum and, secondly, stresses the string tensionally along the neck to provide upon vibration, an appropriate musical tone. The rotation of the spindle or winding drum is typically manipulated by means of a tuning key which affords the musician a means to tune the string by increasing or decreasing the string tension.
Typically, this rotation of the string winding spindle is accomplished by use of a worm-gear engaged by a worm. The worm-gear is arranged in a position axially common with the winding spindle and is typically fixed to it at some distance from the string windings. The connecting shaft between the spindle and worm-gear is supported by a bearing arrangement to permit rotation. Usually some form of thrust bearings are employed to maintain the proper operating position of the worm-gear in relation to the worm. Ordinarily the worm and the associated shaft is mounted in a bearing structure and provided with means to prevent its longitudinal displacement while permitting free rotation. The outer extremity is provided with a handle means, commonly referred to as the tuning key, to facilitate the manual turning of the worm shaft and hence the worm-gear to provide rotation of the winding spindle. In instruments of high quality there is usually a rotation-retarding brake on the worm-shaft. It is commonly understood that the engagement of a worm with a worm-gear provides a locking of the rotation of the gear. Under certain circumstances such as vibrations of frequencies in the audible range, rotational force on the gear may be transmitted to the worm, causing its rotation and allowing the instrument to become un-tuned while being played. An increased friction applied to the worm or its shaft, usually a spring loaded device, minimizes or prevents this undesirable reaction.
However, in prior art constructions, replacement of broken string, requires an inordinate amount of effort and time to accomplish several turns of the new replacement string onto the winding spindle. In many instances, three or four complete revolutions of the string around the winding spindle is required to achieve a pre-tuned degree of tension in the string beginning with the initially relaxed condition of the new string attached to the spindle.
Since most worm to worm-gear ratios in instruments of this kind are of a high magnitude, such as fifteen to one for example, each turn of the winding spindle requires approximately thirty typical wrist-finger motions applied to the turning key to rotate the worm shaft. Therefore to accomplish three or four winding spindle revolutions, ninety to one hundred and twenty finger-wrist motions are required.
If six strings are replaced, several hundred time-consuming finger-wrist rotations are required merely to re-string the instrument. The present invention preserves the advantages of the prior art constructions, however, it offers a convenient means to directly turn the winding spindle in a one to one ratio and eliminate the menial, often aggravating requirement of an undue multiplicity of finger-wrist motions to attach the strings to the instrument and to merely obtain the pre-tuned degree of string tension necessary prior to fine tuning of each string.